In the hydrocarbon industry, many different types of tools are introduced to the downhole environment for a variety of different purposes. Some of these tools are meant to be further modified in the downhole environment at selected times relative to other installations or for independent reasons. For example, production tubes are often used in the downhole environment and are post-installation modified by creating openings therein vernacularly termed “windows” that are used to allow access to other downhole structures such as lateral boreholes. Commonly, such windows are milled in the casing or production tubing using standard milling equipment. While this method has been used for years and certainly results in the creation of an opening, that opening is often of inconsistent shape and is often quite rough at the edge. This makes it difficult to seal a junction, for example, therein as both the shapes of the opening and the roughness are not accurately known.
The art has attempted to use abrasive slurries to cut openings in the downhole environment but has not met with great success due to the settling of abrasive material, wear on machinery, very high operating pressure, etc. With increasing use of multilateral wellbore systems and other constructions using openings that require, or at least are benefited by, sealing or baffling thereat, the art is always receptive to new apparatus and methods for improving openings such as windows.